 Related Questions A sequence generates a serial list of unique numbers for numerical columns of a database's tables. Latest Answer : nice answer soumyanag thumati_nagaraju@yahoo.co.in ... The Primary function of the redo log is to record all changes made to data. Latest Answer : Oracle maintains logs of all transactions against the databse. These transactions are recorded in files called Online Redo log files.These logs are used to recover the database's transaction in their proper order in the evnt of database crash. The redo ... An integrity constraint is a declarative way to define a business rule for a column of a table. Latest Answer : Special requirements for table data:1) allow NULL value2) uniqueness of value3) primary key4) foreign key5) special value size/text/length etc requirementsAll information is stored in Data Dictionary. ... Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ? No. NOT NULL Constraint - Disallows Nulls in a table's column.UNIQUE Constraint - Disallows duplicate values in a column or set of columns.PRIMARY KEY Constraint - Disallows duplicate values and Nulls A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls. Latest Answer : A table can have any number unique keys but a single primary key ... UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data.DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted. Latest Answer : Foreign key value must exist as PK value on some other  table...FK value can be null but PK can't ... If a foreign key reference a parent key of the same table is called self-referential integrity constraint. Latest Answer : Self referential integrity constraint refers to two columns related by referential integrity which belong to the same table.For example ManagerId column in employees table is a foreign key which refers to EmployeeId in the same table. ... The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain sub queries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or Latest Answer : A check constraint allows you to specify a condition on each row in a table. Note: A check constraint can NOT be defined on a VIEW. The check constraint defined on a table must refer to only columns in that table. It can not refer to columns in other ... SID (System Identifier) : A SID (almost) uniquely identifies an instance. Actually, $ORACLE_HOME, $ORACLE_SID and $HOSTNAME identify an instance uniquely. The SID is 64 characters, or Latest Answer : SID is used when we want to login as a local user Global Database name is used when we want to login as a remote login user ...
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